Distributed packet switching systems provide customers with packet switching service on a modular basis allowing incremental growth in the packet switching capacity of the system as the number of users increases. One example of a distributed packet switching architecture is the arrangement disclosed in U.S. Pat. No. 4,596,010 issued to M. W. Beckner et al. on June 17, 1986. In the exemplary embodiment of the Beckner patent, a number of switching modules are interconnected by a central time-multiplexed switch. The modules include both packet switching and circuit switching units for intra-module communication. The central time-multiplexed switch interconnects the module circuit switching units for inter-module circuit-switched communication. Predetermined channels of the central switch otherwise available for carrying inter-module circuit-switched traffic, are permanently established between each pair of module packet switching units for inter-module packet communication. Although the Beckner embodiment advantageously provides packet switching service in a manner allowing incremental growth, particularly when a relatively small number of switching modules each serve users having a high community of interest, the limitation on the inter-module packet traffic capacity imposed by the permanent pairwise assignment of central switch channels substantially limits the packet switching performance of the system, particularly as the number of switching modules and the amount of inter-module packet traffic both increase. The limitation becomes even more serious when the techniques of packet communication are extended beyond digital data communications to other types of information transfer, e.g., voice and image communication.
In view of the foregoing, a recognized problem in the art is the restricted packet traffic capacity between a limited number of switching modules resulting from the permanent pairwise assignment of central switch channels in known distributed packet switching systems.